Going door-to-door can be a taxing enterprise, so why not let your 'tweenager combine work and relaxation with this spa costume?
First, have her put on a plush terry bathrobe and wrap up her 'do in a hand towel secured with a safety pin and covered with an eye mask.
Press on some fake nails and eyelashes for the full treatment look.
Apply green face paint, leaving an inch around the eyes and mouth for a mask effect.
Have her grab a gift bag, comb, and handheld mirror, put on a pair of slippers, and take a deep, relaxing breath before heading out on the town.